An anonymous reader writes: New Scientist says that attaching electrodes to the skin for monitoring brain activity (for example when "installing brain implants that can allow disabled people to control machines using their mind") is "tricky", especially on a "hairy scalp", so the new solution from the University of Pittsbugh is an "electrode that screws into the skin": its "teeth dig into the upper layer of skin and become fixed in place, maintaining good electrical contact".
They say that the thing "should be pain-free". (note: it does not go through the skull!)